The Chicago Department of Public Health (CDPH) proposes to maintain an ongoing HIV behavioral surveillance system among groups at increased risk for acquiring HIV infection in Chicago. This system will be part of the CDC National HIV Behavioral Surveillance system (NHBS). The aims of this system will be to ascertain the prevalence of and trends in HIV risk behaviors and HIV infection among adults at high risk for HIV infection. Trends in accessibility and utilization of HIV prevention programs will also be ascertained. Data collection will rotate each year for the five years of this cooperative agreement among men who have sex with men (MSM-3 in 2011 and MSM-4 in 2014), injecting drug users (IDU-3 in 2012 and IDU-4 in 2015), and heterosexuals at increased risk for HIV infection (HET-3 in 2013). In addition, to these core NHBS activities, we propose to implement behavioral surveillance among male-to- female (MTF) transgender women during 2011 (THBS) and to conduct Hepatitis B &C testing during each cycle to ascertain hepatitis seroprevalence and associated trends in hepatitis-related risk behaviors among adults at high risk for HIV infection. Activities for each cycle will consist of conducting formative research, implementing a sampling methodology to systematically conduct community-based surveys and HIV antibody testing and Hepatitis B/C testing, data analysis and dissemination and project evaluation. All activities will be conducted in collaboration with local community-based organizations (CBO), community planning groups (CP6), academic researchers, and the Centers for Disease Control and Prevention (CDC). This announcement provides an opportunity to capitalize on eight years of experience successfully conducting NHBS and recruiting at-risk individuals from non-health care community settings using scientifically sound methodologies to maintain an ongoing system for surveillance of behaviors related to HIV acquisition. The proposed behavioral surveillance system will provided relevant, timely, and high-quality risk and prevention behavior data, an essential component in helping local community planning groups and help CDPH construct evidence-based plans to appropriately direct local HIV prevention and evaluation efforts.